IMPORTANT: Added overlay filesystem aufs to kernel sources to overlay /system/bin and other directories on the system partition. This will also allow to deliver additional system libraries and apps with our boot.img file. The first aufs branch always points to a tmpfs file system, which allows non-persistent write access to the overlayed directories. As aufs does not set correct selinux contexts and as some selinux rules forbid to create raw sockets for unpriviledged users, I configured selinux to be perimissive by recompiling and replacing the /init binary.